Five Generation Seafood Gumbo

Name: Five-Generation Seafood Gumbo
Ingredients: 3 to 4 chicken backs; 1 dozen large crabs; 1 pouch crab boil mix; 1 tablespoon salt and pepper; 6 ounces tomato paste; 1 pint canned chopped tomatoes; 2 medium onions, diced; 2 medium green peppers, diced; 2 cups celery stalks, diced; 4 cups chopped okra, more to taste; 8 to 10 garlic cloves, finely chopped; 1 1/2 cups shortening (half bacon grease, half Crisco, or all lard); 2 cups all-purpose flour, or as needed; 3 tablespoons granulated sugar; 4 pounds raw shrimp, peeled, more to taste; 1 pint shucked oysters; 1 pint picked, cooked crab meat; 2 teaspoons gumbo filé powder